Not sure where the line between "emotional support animal" and "service dog" is, or even if it matters in this case

Then right after you get that going, are you starting a BP Addicts Support Group?

do the numbers support it?

If things are unraveling for them, I would call their emergency contact and get their support system involved. 

You keep hearing about what a threat it is to use non-licensed $20 an hour guys who might come and repair a wall a tenant's kid knocked a hole in.

No matter how much screening you do or rules you have in the rental agreement, your tenants can be a contributing factor.I'd rather improve a neighborhood with involved citizens, grant money, the support of the city, and relationships with other landlords than have it legislated.

The difference is in fee simple there are two separate physical lots, and you just happen to share a common wall with 0 separation between the two units.

Went back to the home after the auction and noticed one of the walls in the basement was leaning in and cracked badly. 

If you can be crystal clear and provide examples, then you're more likely to get some support from the agents.  

The interior was stripped down to studs, you could actually see daylight through the walls.